condition mean min max ZT0-3 3.9 3.9 3.9 ZT4-7 8.6 8.6 8.6 ZT8-11 17.450000000000003 17.450000000000003 17.450000000000003 ZT12-15 24.25 24.25 24.25 ZT16-19 16.95 16.95 16.95 ZT20-23 4.35 4.35 4.35